1. Field of the Invention:
The present invention relates to an apparatus for generating a deep U-shaped vortex, and more particularly to the use of such a device as an amusement ride to allow passengers to be in the center of a swirling vortex of water.
2. Brief Description of the Prior Art:
The vortex is a fluid-flow phenomenon observed in unbaffled, axially stirred, vertical vessels. Generally, the word "vortex" refers to the deep-welling fluid flow of a liquid, involving rotation about an axis, especially as in a whirlpool. Technically, a vortex is produced by the centrifugal force acting on the rotating liquid. The centrifugal force, due to rotation, acts upon the mass of liquid, drawing it away from the center and causing it to rise along the wall of the vessel, thereby resulting in a deep well of air along the central axis of rotation. The overall phenomenon of liquid rising at the outer perimeter due to the centrifugal force created by the rotation of the liquid mass, and the resultant deep-welling of air, is termed a vortex.
"Man-made" deep vortices typically occur in the central region of mechanically rotated, symmetric, unbaffled vessels containing low viscous liquids, such as water. Naturally-occurring vortices can be observed at the eddies of ocean currents and in the wake of other flowing masses of water past stationary bodies. For example, a well defined, naturally-occurring vortex regularly occurs in the Naruto Strait which connects the Inland Sea of Japan and the Pacific Ocean.
OKADA (U.S. Pat. No. 3,635,448) describes a vortex generator placed or formed in the bottom of a pond or pool for generating a decorative vortex within the pond or pool. The OKADA vortex generator includes a vessel with an impeller at the bottom of the vessel, and the vessel having a generally cylindrical wall that is shaped like an inverted cone. The OKADA device is used to create small, decorative vortices on the surface of a pond or pool. Similar devices are shown in Japanese patents 3-257262 and 3-257263, which were both issued to KAMIKUBO.
BARBER (U.S. Pat. No. 4,836,521) shows a whirlpool amusement ride, which simulates traverse of the edge of a whirlpool. In BARBER, passengers ride on a floating vehicle which travels up and over a rotatable annular member which rotates around a pond of water. In contrast to the current invention, BARBER includes a shallow whirlpool, and the passenger vehicles float on the water's surface.
Previous vortex generators create V-shaped vortices which are conducive to mixing. The prior art does not teach the creation of deep U-shaped, near-laminar flow vortices.